1. Field of the Invention
The present invention relates to a metamaterial having a specific refractive index such as a negative refractive index in an electromagnetic field including light.
2. Description of the Related Art
A metamaterial has been discussed in recent years. The metamaterial is a material that is artificially formed from a metal, a dielectric substance, a magnetic substance and the like in a structure that is smaller than a wavelength of an incident light and artificially changes a permittivity and a permeability of a medium.
If the metamaterial is configured to have negative values in both of the permittivity and the permeability, a negative refractive index can be obtained. New optical phenomena such as image formation over a diffraction limit (complete image formation) can be obtained using the negative refractive index. Impedance can be arbitrary controlled by independently controlling the permittivity and the permeability, and thus, a structure in which complete reflection and a reflectivity are reduced can be obtained.
In addition to the above, it has been discussed to apply new optical properties that do not occur in the nature by controlling the permittivity and the permeability. A structure in which unit lattices having a micro-resonator are arrayed in matrices has been discussed as a structure in which the permittivity and the permeability are artificially controlled in Physical Review Letter, 95: 137404 (2005 (hereinafter referred to as a “non-patent literature 1”).
However, when the structure described in the non-patent literature 1 is applied to a region with a short wavelength such as a near-infrared region and a visible region, it is necessary to shorten a resonance wavelength of a magnetic field or an electric field. To shorten the resonance wavelength, the unit lattice (micro-resonator) could be further downsized simply. However, a size of the unit lattice in the near-infrared region and the visible region becomes approximately 100 nm or smaller, and it becomes very difficult to fabricate such a structure.